HLA polymorphism in Sudanese renal donors.

The main objective of this study is to provide a database for renal transplantation in Sudan and to determine the HLA antigens and haplotype frequencies (HFs) in the study subjects. HLA typing was performed using the complement-dependant lymphocytotoxicity test in 250 unrelated healthy individuals selected as donors in the Sudanese Renal Transplantation Program. Considerable polymorphism was observed at each locus; A2 (0.28), A30 (0.12), A3 (0.09), A24 (0.09), A1 (0.09), and A68 (0.06) were the most frequent antigens in the A locus, while B51 (0.092), B41 (0.081), B39 (0.078), B57 (0.060), B35 (0.068), B 50 (0.053) and B 52 (0.051) were the most common B locus antigens. DR13 (0.444) and DR15 (0.160) showed the highest antigen frequencies (AFs) in the DR locus. In the DQ locus, DQ1 showed the highest gene frequency (0.498), while DQ2 and DQ3 AFs were (0.185) and (0.238), respectively. The most common HLA-A and -B haplotypes in positive linkage disequilibrium were A24, B38; A1, B7; and A3, B52. The common HLA-A and -B HFs in positive linkage disequilibrium in the main three tribe-stocks of the study subjects (Gaalia, Nile Nubian and Johyna) were A24, B38 for Gaalia; A24, B38 and A2, B7 for Johyna; and A2, B64 and A3, B53 for Nile Nubian. These results suggest that both class I and class II polymorphisms of the study subjects depict considerable heterogeneity, which reflects recent admixture of this group with neighboring Arabs and African populations.

Informed decision-making before changing to RDT: a comparison of microscopy, rapid diagnostic test and molecular techniques for the diagnosis and identification of malaria parasites in Kassala, eastern Sudan.

OBJECTIVES: Rapid diagnostic tests (RDTs) are promoted for the diagnosis of malaria in many countries. The question arises whether laboratories where the current method of diagnosis is microscopy should also switch to RDT. This problem was studied in Kassala, Sudan where the issue of switching to RDT is under discussion. METHODS: Two hundred and three blood samples were collected from febrile patients suspected of having malaria. These were subsequently analysed with microscopy, RDT (SD Bioline P.f/P.v) and PCR for the detection and identification of Plasmodium parasites. RESULTS: Malaria parasites were detected in 36 blood samples when examined microscopically, 54 (26.6%) samples were found positive for malaria parasites by RDT, and 44 samples were positive by PCR. Further analysis showed that the RDT used in our study resulted in a relatively high number of false positive samples. When microscopy was compared with PCR, an agreement of 96.1% and k = 0.88 (sensitivity 85.7% and specificity 100%) was found. However, when RDT was compared with PCR, an agreement of only 81.2 and k = 0.48 (sensitivity 69% and specificity 84%) was found. CONCLUSION: PCR has proven to be one of the most specific and sensitive diagnostic methods, particularly for malaria cases with low parasitaemia. However, this technique has limitations in its routine use under resource-limited conditions, such as our study location. At present, based on these results, microscopy remains the best option for routine diagnosis of malaria in Kassala, eastern Sudan.